From 58f1fd5a79ce9468ed1adecf2d0beed5abe72c00 Mon Sep 17 00:00:00 2001
From: David du Colombier <0intro@gmail.com>
Date: Wed, 19 Jun 1991 00:00:00 +0000
Subject: [PATCH] Plan 9 from Bell Labs 1991-06-19

---
 pc/l.s         | 61 +++++++++++++++++++++++++++++++++++---------------
 port/devbit.c  |  8 ++++---
 port/fault.c   | 19 +++++++++-------
 port/portfns.h |  2 +-
 port/sysproc.c |  2 +-
 5 files changed, 61 insertions(+), 31 deletions(-)

diff --git a/pc/l.s b/pc/l.s
index e4e287c95144dbae4db927f821ec6068bd96e644..d657c1567dd9153011f2f7ca9cafdd6913709536 100644
--- a/pc/l.s
+++ b/pc/l.s
@@ -1,6 +1,6 @@
 
 /*
- * Boot first processor
+ *  boot first processor
  */
 TEXT	start(SB),$0
 
@@ -9,6 +9,9 @@ TEXT	start(SB),$0
 	/* never returns */
 
 
+/*
+ *  trap vector, each instruction is 4 bytes long
+ */
 TEXT	traptab(SB),$0
 
 	CALL	noerrcode(SB)	/* divide */
@@ -270,23 +273,45 @@ TEXT	traptab(SB),$0
 	CALL	noerrcode(SB)
 
 TEXT	noerrcode(SB),$0
-	PUSH	EAX
-	/* drop through */
+
+	PUSHL	EAX
+	MOVL	4(ESP),EAX
+/*	JMP	george /**/
+
 TEXT	errcode(SB),$0
-	PUSH	EAX
-	PUSH	EBX
-	PUSH	ECX
-	PUSH	EDX
-	PUSH	EBP
-	PUSH	ESI
-	PUSH	EDI
+
+	XCHGL	(ESP),EAX
+	/* fall through */
+
+TEXT	saveregs(SB),$0
+
+george:
+	PUSHL	EBX
+	MOVL	$noerrcode(SB),EBX	/* calculate trap number */
+	SUBL	EAX,EBX			/* ... */
+	SHRL	$1,EBX			/* ... */
+	PUSHL	ECX
+	PUSHL	EDX
+	PUSHL	EBP
+	PUSHL	ESI
+	PUSHL	EDI
+	PUSHL	EBX			/* save trap number */
 	CALL	trap(SB)
-	POP	EDI
-	POP	ESI
-	POP	EBP
-	POP	EDX
-	POP	ECX
-	POP	EBX
-	POP	EAX
-	ADD	$8,ESP	/* jump over error code + return addr */
+	ADDL	$4,ESP			/* drop trap number */
+	POPL	EDI
+	POPL	ESI
+	POPL	EBP
+	POPL	EDX
+	POPL	ECX
+	POPL	EBX
+	POPL	EAX
+	ADDL	$4,ESP			/* drop error code */
 	IRET
+
+TEXT	trap(SB),$0
+
+	RET
+
+TEXT	main(SB),$0
+
+	RET
diff --git a/port/devbit.c b/port/devbit.c
index e3eb10dec8182b13d598f076b39b9bdff9b06f87..42f1c986baf960d4741d206ff4199c9b8cecf181 100644
--- a/port/devbit.c
+++ b/port/devbit.c
@@ -1009,9 +1009,11 @@ bitwrite(Chan *c, void *va, long n, ulong offset)
 				error(Ebadblt);
 			pt1.x = GLONG(p+1);
 			pt1.y = GLONG(p+5);
-			mouse.xy = pt1;
-			mouse.track = 1;
-			mouseclock();
+			if(!eqpt(mouse.xy, pt1)){
+				mouse.xy = pt1;
+				mouse.track = 1;
+				mouseclock();
+			}
 			m -= 9;
 			p += 9;
 			break;
diff --git a/port/fault.c b/port/fault.c
index 826daf112a00cadd8718a137b00ffcf2115bfe54..1cec35658293163a71d8fedd26d84bfa3ef6cfc4 100644
--- a/port/fault.c
+++ b/port/fault.c
@@ -264,7 +264,7 @@ validaddr(ulong addr, ulong len, int write)
  * &s[0] is known to be a valid address.
  */
 void*
-vmemchr(void *s, int c, int n)
+vmemchr(void *s, int c, ulong n)
 {
 	int m;
 	char *t;
@@ -272,18 +272,21 @@ vmemchr(void *s, int c, int n)
 
 	a = (ulong)s;
 	m = BY2PG - (a & (BY2PG-1));
-	if(m < n){
-		t = vmemchr(s, c, m);
+	while(n){
+		if(n < m)
+			m = n;
+		t = memchr(s, c, m);
 		if(t)
 			return t;
+		if(n == m)
+			return 0;
 		if(!(a & KZERO))
 			validaddr(a+m, 1, 0);
-		return vmemchr((void*)(a+m), c, n-m);
+		n -= m;
+		a += m;
+		m = BY2PG;
 	}
-	/*
-	 * All in one page
-	 */
-	return memchr(s, c, n);
+	return 0;
 }
 
 Seg*
diff --git a/port/portfns.h b/port/portfns.h
index 418a2906d3d56404f40f6df12eaeda19f1fcd3bc..45a6f0261246ee8ea82c12965d01739a14e3b9c7 100644
--- a/port/portfns.h
+++ b/port/portfns.h
@@ -187,6 +187,6 @@ void	unusepage(Page*, int);
 void	usepage(Page*, int);
 void	userinit(void);
 void	validaddr(ulong, ulong, int);
-void*	vmemchr(void*, int, int);
+void*	vmemchr(void*, int, ulong);
 void	wakeme(Alarm*);
 void	wakeup(Rendez*);
diff --git a/port/sysproc.c b/port/sysproc.c
index b1052d685634a988f3fccab095e94e20610b6cce..88a62eda0ccddd69b870d3561b14bc85981d0d23 100644
--- a/port/sysproc.c
+++ b/port/sysproc.c
@@ -237,7 +237,7 @@ sysexec(ulong *arg)
 		if(((ulong)argp&(BY2PG-1)) < BY2WD)
 			validaddr((ulong)argp, BY2WD, 0);
 		validaddr((ulong)a, 1, 0);
-		nbytes += (vmemchr(a, 0, 0xFFFFFFFF) - a) + 1;
+		nbytes += (vmemchr(a, 0, ~0) - a) + 1;
 		nargs++;
 	}
 	ssize = BY2WD*(nargs+1) + ((nbytes+(BY2WD-1)) & ~(BY2WD-1));